在 C++ 中解析逗号分隔的整数/整数范围 [英] Parse comma-separated ints/int-ranges in C++

问题描述

在 C++ 中给定一个包含范围和单个数字的字符串:

Given a string in C++ containing ranges and single numbers of the kind:

"2,3,4,7-9"

我想将其解析为以下形式的向量:

I want to parse it into a vector of the form:

2,3,4,7,8,9

如果数字由 - 分隔，那么我想推送范围内的所有数字.否则我想推送一个数字.

If the numbers are separated by a - then I want to push all of the numbers in the range. Otherwise I want to push a single number.

我尝试使用这段代码:

const char *NumX = "2,3,4-7";
std::vector<int> inputs;
std::istringstream in( NumX );
std::copy( std::istream_iterator<int>( in ), std::istream_iterator<int>(),
           std::back_inserter( inputs ) );

问题是它不适用于范围.它只取字符串中的数字，而不是范围内的所有数字.

The problem was that it did not work for the ranges. It only took the numbers in the string, not all of the numbers in the range.

推荐答案

除了@J.Schultke 的优秀例子，我建议以下列方式使用正则表达式:

Apart from @J. Schultke's excellent example, I suggest the use of regexes in the following way:

#include <algorithm>
#include <iostream>
#include <regex>
#include <string>
#include <vector>

void process(std::string str, std::vector<int>& num_vec) {
    str.erase(--str.end());
    for (int i = str.front() - '0'; i <= str.back() - '0'; i++) {
        num_vec.push_back(i);                                                     
    }
}

int main() {
    std::string str("1,2,3,5-6,7,8");
    str += "#";
    std::regex vec_of_blocks(".*?\,|.*?\#");
    auto blocks_begin = std::sregex_iterator(str.begin(), str.end(), vec_of_blocks);
    auto blocks_end = std::sregex_iterator();
    std::vector<int> vec_of_numbers;
    for (std::sregex_iterator regex_it = blocks_begin; regex_it != blocks_end; regex_it++) {
        std::smatch match = *regex_it;
        std::string block = match.str();
        if (std::find(block.begin(), block.end(), '-') != block.end()) {
            process(block, vec_of_numbers);
        }
        else {
            vec_of_numbers.push_back(std::atoi(block.c_str()));
        }
    }
    return 0;
}

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当然，您仍然需要一点验证，但是，这会让您开始.

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Of course, you still need a tad bit validation, however, this will get you started.

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